Jim's Pond, Homemade Bio-Filter and DIY Venturi Spot

Welcome to Jim's Pond Blog. Like many people I am a keen "ponder". I have a 400 gallon garden pond with carp, ghost-koi and shubunkins. I started my Leisure website to share ideas on my own DIY design for a homemade Skippy style bio filter, with pre-filter and venturis. My website has many photos detailing the construction of an unobtrusive bio-filter suitable for small ponds, and what I have learnt along the way.Please feel free to post your own comments!

Tuesday, July 10, 2007

Blanket Weed under the Microscope

Personally I use a concentrated liquid form of Barley Straw Extract at the beginning of the year to try and combat the worst of the blanket weed (although this liquid form can be expensive).

Barley straw is a more natural method of combating the blasted weed, but even at the start of the year before the various enzymes and bacteria start doing their work blanket weed can build up quite quickly in the pond.

In a stream you tend to get it all year long, simply because the water is shallow, and the sunlight has the most impact, therefore it has to be removed by hand regularly.

Like so many people, in the past I tried using chemical based products and solutions to treat blanket weed, but the main trouble with these is they just breakdown the structure of the blanket weed making it slippery and slimey and even more difficult to remove from the pond.

I prefer to let the weed grow to a suitable length, then use a cane stick to dip into the water and "twizzle" it in the blanket weed which quite easily attaches itself and wraps around the cane.

I just keep twizzling to "wind" in all the weed, which eventually breaks off leaving only short lengths attached to the pond sides and bottom.

After a bit of twizzling I then use a sharp Stanley knife to cut the blanket weed away from the cane. A twizzled lump of blanket weed is really very tough stuff and won't easily pull off the cane.

This cane method just isn't possible if you use chemicals to break down blanket weed.

Another alternative which I use is my pond hoover, but generally I use that to clean excess sediment, leaves etc from the bottom of the pond.

After physically removing as much as possible, I then give another good dose of barley straw.After this first major growth in the spring, the pond balance and enzymes seem to get the upper hand and the blanket weed is much less of a problem for the remainder of the year.

Since building my DIY bio-filter I have never had a problem with green water.

Yes, blanket weed sometimes at the start of the year, but never green water all year long.

If this is your first year with a new pond, do not be surprised if you get a couple of green water blooms a couple of weeks or months apart as the pond and bio-filter all establish their equilibrium. Large pond plants are good additions but they need time to grow and then they will use excess nitrates (essentially fertiliser) produced by the bacteria life cycle in your pond, so starving phytoplankton of nitrates (they are the little blighters who actually make the water go green).

Did you know that phytoplankton is generally always there in your pond during the summer? It is simply "photosynthesis" caused by sunlight which makes them turn green, and when they multiply in their thousands and millions because of too much nitrate (think fertiliser), this is what causes your pond water to become green pea soup.

During daylight these microscopic plant-cum-animals absorb carbon dioxide and give out oxygen - good for your fish - but at night the reverse happens, and they take in oxygen, and give out carbon dioxide. This is when your fish can suffocate if you have a really bad green water problem!!!

Now to finish off you really should marvel at the beauty and mechanics of these tiny creatures.

Too much fish food!

Grrrr!

Why is it my grandson insists on grabbing huge handfuls of fish food, and chucking it into my pond, the little blighter. I've told him not to do it before. I know he enjoys feeding the fish, but I don't think he takes on the fact they aren't as hungry as he can be :o)

Actually I think he must have realised his mistake, because I later discovered he had used the fish net to remove some of the surplus and had tried to hide it in the bin. But there was still loads of pellets floating around on the surface.

Should I put scrubbies in the bottom of my Hozelock Cyprio bio-filter?

Recently I got an email from someone asking about Cyprio bio-filters. It was much along the lines of the problems I have encountered and written about in my Ponding website.

"Hi ....just been reading your page on how to make a pond filter ...very informative ...wish I had found it before buying the Hozeloc Cyprio off Ebay , Although it seems to be working ok (I have checked size and thats fine) it does need the foam cleaning (I rinse it as instructions say using the water from the filter) every couple of days...my point in emailing you is to ask if you think putting some "scrubbies" in the bottom of the filter will help increase my bacteria population ? There are already some black ball things in there ....but not many......and not a lot happening to them....pond is new and has been going for about 2 months . I recently had the water checked and found I had traces of ammonia .25 . I was told this could sort its self out as the pond matures but thought I could give nature a helping hand !!"

Hi Christine,

The problem is always one of matching the right size pumps/filter for the size of pond. Unfortunately I think that the Hozelock Cyprios really are not man enough for the job, and their design is probably more suited to decorative feature ponds rather than ones that have fish in, because they block up far too quickly/easily.

I think part of the problem is that because they are pressurised units with no settling area for fish waste, debris and weed to "settle out" to a drainage point, all that muck just becomes compressed in the foam filters, to the point where they almost feel "solid" when you squeeze them out!

The idea of the bio-balls in the bottom of the filter is to provide high surface area for the bacteria to develop on. I think that if you put scrubbies (green kitchen scouring pads) in the bottom of your Cyprio (which is essentially a sealed unit) you will just end up giving the filter even more material to clog, and for you to clean.

Probably more important to help your pond mature faster is to give regular fresh doses of bacteria. I use both a solution type for "injecting" into my bio-filter, and a granular type for spreading in the main pond.

I wonder how many and which type of fish you have? During early pond maturation stage you should just have smaller, hardy types of fish, goldfish, shubunkins, to help build a mild ammonia level for the bacteria and bio-filter to start building up the nitrification cycle. It is only later when the pond has an established eco-cycle that you should put larger fish (more susceptible to disease and less tolerant of ammonia) such as koi.

Really your Cyprio will probably perform the job it needs to do, as long as you keep cleaning it out, but my feeling certainly with the smaller models of the Cyprio is that because they clog so quickly, and you have to clean it out every couple of days, then you are constantly disturbing the bacteria trying to develop inside it, and so this type of bio-filter really only ever acts as a mechanical filter, and I believe doesn't deserve to be called a "bio" filter.

As mentioned above a settling tank or section within the filter setup plays a major factor in helping remove solids waste, and letting the scrubbies in my own filter design do their work without becoming so clogged. Yes - the scrubbies do become filthy over time, but it is extremely fine sediment, which the bacteria is working on and turning back into minerals.

Also consider increasing the number of large plants in your pond, and also you might think about a "veggy" filter as part of a waterfall. A veggy filter acts both as a mechanical filter with its fine root system, and as a bio-filter where bacteria can feed on the fish waste and ammonia, turning it into nitrates which the plants in the veggy filter can then gobble up as fertiliser. In my pond I have plants in the top of my bio-filter, more scrubbies and cress inside the decorative water urn at the top of my waterfall, and then a bog area in the lower section of the stream. You probably don't have a stream, all I'm saying is that each of these features helps aid the growth of even more bacteria and plants, so I'm maximising mother nature to the full!

Do you have some kind of pre-filter cage on the pump in your pond? Something there could help to reduce the amount of muck going directly into the Cyprio.

Overall I think its the sum of many things which help keep a pond healthy and clean and bright.

About Me

I work with computers by day, but enjoy keeping my pond and fish healthy with a DIY bio-filter and venturi in my leisure time, details of which you can find on my web site. I love music of all kinds, and with a friend also composed a music CD based on Tolkiens Lord of the Rings. Other than that I enjoy the Internet, astronomy, technology in general, and dabble with Internet Marketing.